AKo on button early in 180

[xoom]

A couple of hands into the tournament. SB doubled up on first with AA against KQo on AKx board. Should I be willing to put my tournament on the line here in these situations against unknowns? Any comments on this hand at all is welcome, as I am going through a bit of a downswing at the moment.

Stack sizes:
MP2: t1420
Hero: t1540
SB: t3000


Pre-flop: (8 players) Hero is Button with A[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/diamond.gif[/img]
3 folds, <font color="#cc0000">MP2 raises to t40</font>, CO folds, <font color="#cc0000">Hero raises to t140</font>, SB calls t130 <font color="#aaaaaa">(pot was t210)</font>, BB folds, MP2 calls t100 <font color="#aaaaaa">(pot was t340)</font>.

Flop: T[img]/images/graemlins/diamond.gif[/img] A[img]/images/graemlins/club.gif[/img] 8[img]/images/graemlins/spade.gif[/img] (t440, 3 players)
SB checks, MP2 checks, <font color="#cc0000">Hero bets t240</font>, <font color="#cc0000">SB raises to t480</font>, MP2 folds, Hero calls t240 <font color="#aaaaaa">(pot was t1160)</font>.

Turn: 6[img]/images/graemlins/diamond.gif[/img] (t1400, 2 players)
<font color="#cc0000">SB bets t600</font>, <font color="#cc0000">Hero raises all-in t920</font>, SB calls t320 <font color="#aaaaaa">(pot was t2920)</font>.

River: 5[img]/images/graemlins/heart.gif[/img] (t3240, 1 player + 1 all-in - Main pot: t3240)


Results:
Final pot: t3240